The passenger compartment of vehicles incorporates a number of composite contoured trim panels in order to impart the desired aesthetic appearance and to further provide insulation against the transmission of noises into the interior of a passenger compartment. Such trim panels also serve as insulation against heat transmission and in some instances, provide safety protection to the passengers due to their impact absorption characteristics.
Of the several trim panels conventionally employed, the headliner of headlining panel adapted to be positioned adjacent to the underside of steel roof panels has presented a continuing problem due to its size, weight, cost in fabrication and installation, and requirements of stability and freedom from warpage over prolonged time periods in spite of the wide fluctuation in ambient temperature and humidity conditions. Cloth and fabric-backed plastic headlinings at one time had been in widespread use, which were of the so-called "cut-and-sew" type comprising a series of sections sewn together and which were supported at longitudinally spaced intervals by a series of bows or lifting wires extending transversely beneath the roof panel and joined at their ends to the side edges of the automobile body. Headlinings of the foregoing type were highly labor intensive and also costly to manufacture and to a large extent, have been replaced by so-called "snap-in" type headliners comprising one or a series of shape-retaining panels which are adapted to be supported along their peripheral edge by a trim channel extending adjacent to the roof panel of the automobile. Typical of such prior art "snap-in" headliners are those disclosed in U.S. Pat. Nos. 3,506,532 and 3,507,728, the substance of which are incorporated herein by reference.
While such snap-in headliner panels of the types heretofore known have overcome many of the problems associated with cloth and fabric-type prior art headliners, some problems still remain. For example, some prior art headliner constructions have necessitated the use of unsightly score lines or creases in order to enable the attainment of the desired contouring and installation of the panel in the vehicle. Other headliner constructions have been characterized by unsatisfactory mechanical properties, such as, for example, an excessive weight-to-strength-to-bulk ratio, while others have had insufficient resistance to sag or warpage as a result of severe fluctuations in ambient temperature and humidity conditions. While some headliner constructions have been adequate for use in small compact cars, such structures have been unacceptable for use in larger full-size vehicles due to the greater unsupported expanse of the headliner, resulting in objectionable sagging, particularly when exposed to elevated temperatures approaching 200.degree. F. In order to overcome such structural shortcomings, it has heretofore been proposed to employ fiberglass reinforced plastic laminates, but such headliners have not received widespread commercial acceptance due to their high cost of manufacture and the relatively expensive tooling required.
The present invention provides a contoured resilient trim panel and method for producing such trim panel which overcomes many of the problems associated with snap-in type headliners of the types previously known. The trim panel of the present invention is of economical cost, is light in weight, has a desired high strength-to-weight ratio, is versatile in its use and application to different styling motifs and vehicle sizes, can readily be thermoformed such as by vacuum molding to the desired contour and can be formed to further include suitable embossments for visor recesses, speaker housings, dome lights and the like; is stable and heat resistant and does not undergo objectionable sagging even when heated to temperatures up to about 200.degree. F.